1. Field of the Invention
The present invention relates to a circuit device, with which conductive patterns, which are to be electrodes, are exposed from side surfaces of an insulating resin that seals the entire circuit device, and a method of manufacturing such a circuit device.
2. Description of the Related Art
Conventionally, due to being employed in portable telephones, portable computers, etc., circuit devices that are set in electronic equipment have been demanded to be compact, thin, and lightweight. Among related-art circuit devices, there is that which is called a CSP (Chip Size Package).
FIG. 18 shows a CSP 50, which is slightly larger than a chip size and employs a glass epoxy substrate 51 as the supporting substrate. Here, a description shall be provided for the case where a transistor chip 56 is mounted onto glass epoxy substrate 51.
A first electrode 52, a second electrode 53, and a die pad 57 are formed on the surface of this glass epoxy substrate 51. And a first rear surface electrode 54 and a second rear surface electrode 55 are formed on the rear surface of the glass epoxy substrate 51. Via through holes 59, the first electrode 52 is electrically connected with first rear surface electrode 54 and second electrode 53 is electrically connected with second rear surface electrode 55. The transistor chip 55 is affixed in bare form onto die pad 57, the emitter electrode of the transistor is connected via a metal wire 58 to first electrode 52, and the base electrode of the transistor is connected via a metal wire 58 to second electrode 53. Furthermore, a resin layer 60 is provided on glass epoxy substrate 51 so as to cover transistor chip T.
Though employing a glass epoxy substrate 51, the CSP 50, unlike a wafer-scale CSP, has the merits of being simple in the extension structure from chip T to the rear surface electrodes 54 and 55 for external connection and being inexpensive to manufacture.
With the above-described CSP or other related-art type circuit device, first rear surface electrode 54 and second rear surface electrode 55 for electrical connection with the exterior are provided at the rear surface of the device. The device is mounted onto a mother board, etc., by attaching soft solder or other brazing material to the rear surface electrodes by a reflow process, etc. However, after mounting, it was difficult to visually judge whether or not the brazing material has an appropriate shape since the brazing material is formed in the minute gap between the rear surface of CSP 50 and the mother board.
Furthermore, first rear surface electrode 54 and second rear surface electrode 55 are formed on the rear surface of glass epoxy substrate 51 and protrusions are formed due to the thickness of these electrodes. There was thus the problem that the rear surface electrodes, which have been formed in a protruding manner, peeled off in the process of conveying a completed CSP 50.
This preferred embodiment of invention has been made in view of such problems, and an object of this preferred embodiment of invention is to provide a circuit device, with which conductive patterns are exposed from the side surfaces of an insulating resin sealing the entire circuit device, and a method of manufacturing such a circuit device.